Nonlinear mismatches between two cores of saturable nonlinear couplers

The effect of the mismatch in nonlinearities between two cores of a saturable nonlinear coupler is explored. For a passive saturable nonlinear coupler, the impact of a mismatch in the nonlinearities on the operation of the coupler is shown to be interchangeable with that of a linear mismatch (resulting from a difference between the two individual cores in the absence of nonlinearity) except at low power limit. However, when both nonlinear mismatch and linear mismatch are present, new features appear, depending on the mismatches. This is reflected in the emergence of the novel bifurcation (or mode) diagrams which are shown to lead to new devices. Nonlinear couplers that include gain are also examined. It is found that a nonlinear mismatch can lead to the improvement of the switching using nonlinear couplers